The present invention relates generally to devices for scoring tennis games and the like and particularly to such devices in which the score is registered by the position of an indicator element which is movable manually along a linear channel.
Score keeping devices with generally linear but open channels along each of which an indicator element can be slid to register a score have been described in the prior art. In U.S. Pat. No. 2,402,525, a scoring device with a plurality of such channels or slots is provided. The opposing sides of each slot have a series of pairs of spaced indentations formed therein for holding an indicator button in a desired location. To change position from one pair of indentations to the next, the user must force the button against the walls of the slot causing them to give slightly.
A variation in which the walls of such a slot are kept parallel to each other in order to facilitate the retention of an indicator element is disclosed in U.S. Pat. No. 4,172,595. There a tennis tally has specially structured marker pins for scoring the opposing sides of a tennis match which are snapped into engagement with the walls of either of two parallel slots. Cylindrical protrusions arrayed parallel to the slots and between them are situated so that these protrusions can interfere with the movement of the marker pins along the slots and hold each of them in position against accidental dislodgement. The bulkiness of this tennis tally dictates that it be mounted on the bottom end of a .cp10 tennis racket handle to mimimize any effect of its air resistance on the user's game.